Cell to Cell and Long distance Signaling
Braun, David , Ma, Yi , Baker, R. Frank , Slewinski, Tom .
Tie-dyed1 encodes a novel protein controlling carbohydrate accumulation in leaves.
Clonal analyses of maize leaf development have shown that clonal (mother to daughter cell) lineages are arranged longitudinally along the long axis of the leaf. To identify genes coordinating regional leaf identity we screened for mutants with sectors that extend laterally to cells beyond the clonal lineages. A recessive mutant, tie-dyed1 (tdy1), was identified with yellow and green pigmented leaf sectors that violate cell lineage boundaries. We determined that tdy1 sectoring requires high light, is restricted to a narrow developmental time and results in the yellow tissue hyperaccumulating sugars and starch. A clonal mosaic analysis of Tdy1 revealed that a mobile signal, possibly sucrose, derived from the tdy1 mutant tissue is able to induce wild type cells to express the mutant phenotype. Additionally, it suggested that Tdy1 function is restricted to the innermost layer of leaves which contain the veins. From these and other data we propose that TDY1 acts as a sugar flux or an osmotic stress sensor to up-regulate sugar export at a critical time during leaf development. To characterize tdy1 at the molecular level we isolated additional alleles via a directed Mutator (Mu) transposon tag. A tightly linked Mu1 element was cloned, and three additional alleles containing Mu insertions into the same gene verified that we had identified the correct gene. The Mu insertions are all located in the 5’UTR of a novel gene. Expression studies are underway to test our proposed model for TDY1 function. Consistent with our conclusions from the mosaic analysis, preliminary RNA in situ hybridization experiments localize the Tdy1 transcript to the vasculature, and transient expression of TDY1 fusions to GFP localize the protein to endomembranes.
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tie-dyed1 Plant Phys paper
1 - Pennsylvania State University, Biology, 208 Mueller Lab, University Park, PA, 16802, USA
2 - Pennsylvania State University, Biology
Presentation Type: ASPB Minisymposium
Location: Continental C/Hilton
Date: Sunday, July 8th, 2007
Time: 2:25 PM